JP7359800B2 - Balloon seal stress reduction and related systems and manufacturing methods - Google Patents

Description

TECHNICAL FIELD The present disclosure relates generally to reducing balloon seal stress to reduce the occurrence of malfunctions associated with balloon catheters.

Balloon catheters are often used in medical procedures to deploy endoprostheses. In a common situation, a balloon secured to the catheter shaft by a seal is hydraulically inflated, thereby expanding the overlying endoprosthesis from a small diameter for delivery to a large diameter for operation. Balloons used for medical procedures such as percutaneous transluminal angioplasty (PTA) or local drug delivery may require balloon pressures as high as 10 to 30 atmospheres. To prevent or alleviate undesirable balloon failure, it may be beneficial to make the balloon seal more robust or to reduce the stress placed on the seal, especially in high pressure applications.

In addition, reducing the amount of stress applied to the balloon seal may prevent it from maintaining its pre-formed or pre-molded shape, especially when inflated to the working pressure range. It may be beneficial for expandable balloons constructed from such materials. However, these types of materials present problems with the shape of the shoulder region of the balloon upon inflation. In such balloons that use material that can be inflated in the shoulder area, the shape of the shoulder wall surface during inflation is such that the diameter between the working length and the seal is not tapered, e.g. the shoulders are more vertical. It is often thought of as being perpendicular (right angle) or approximately perpendicular, or sometimes vice versa. It may be particularly preformed or shaped of a substantially non-expandable (e.g. non-flexible) material which upon expansion takes on a shoulder shape, e.g. conical, which tapers from the end of the working length towards the balloon seal. This contrasts with balloons made from recycled materials. If the shoulder is not tapered, the stress on the adjacent balloon seal will be increased. A balloon seal where the balloon has a more "right angled" shoulder rather than a conical shape will withstand higher pressures at the seal. Balloons with such shoulder shapes can benefit from designs that reduce such sealing pressure.

The balloons of the present disclosure have shoulder portions that have a load distribution shape, such as by adding a load distribution member.

According to one aspect of the disclosure, the balloon has a body portion that is inflatable to a first diameter and includes a wrapped polymeric material; a second body portion that is each smaller than the first diameter; two seal portions each having a diameter; and two shoulder portions each defining a transition between the first diameter and the second diameter, wherein the at least one shoulder portion The portion includes a load distribution member suitable for inhibiting expansion along at least a portion of the shoulder portion beyond a diameter between the first diameter and the second diameter. The body portion extends between the two shoulders, and the two shoulders and the body portion extend between the two seal portions.

According to another aspect of the invention, the balloon has a body portion inflatable to a first diameter; two seal portions each having a second diameter smaller than the first diameter; The balloon may include two shoulders defining a transition between the diameter and the second diameter, wherein at least one shoulder includes a stepped shape upon inflation of the balloon. There is.

According to another aspect of the invention, a method for reducing hoop stress on a seal portion on an expandable balloon having a body portion and two shoulder portions is provided. , disposing a load distribution member around the balloon along at least a portion of at least one of the two shoulder portions, wherein the balloon includes a wrapped polymeric material. There is.

Various aspects of the disclosure may include various additional or alternative features in any combination. In various embodiments, the wrapped polymeric material may be an expanded fluoropolymer, such as expanded polytetrafluoroethylene. In various embodiments, the outer edge of the body portion and the inner edge of the seal portion may be longitudinally offset from each other. In various embodiments, the load distribution member may include a structural reinforcement member. In various embodiments, the load distribution member may extend along a substantial portion of the shoulder portion. In various embodiments, the shoulder portion may include a tapered shape. In various embodiments, the load distribution member may include a frusto-conical structural reinforcement member. In various embodiments, the load distribution member is wrapped around a conically shaped mandrel and may include an optionally densified or imbibed material. In various embodiments, the load distribution member may include a low expansibility polymeric material shaped into a tapered shape. In various embodiments, the shoulder portion may include a stepped shape. In various embodiments, the load distribution member may be isolated in the middle portion of the shoulder portion. In various embodiments, the load distribution member may include a material that has a higher durometer than the wrapped polymeric material. In various embodiments, the load distribution member may include at least one of densified ePTFE or imbibed ePTFE. In various embodiments, the load distribution member may include multiple wraps of a low expansible polymer membrane. In various embodiments, the load distribution member may be located outside the body portion of the balloon. In various embodiments, the load distribution member may include a pattern cut reinforcing member, optionally Nitinol.

The accompanying drawings are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of the specification, and illustrate embodiments of the disclosure. It serves to explain the principle of the present disclosure together with the description of this specification.

FIG. 1 illustrates a cross-sectional view of a balloon catheter with a right-angled shoulder.

FIG. 2A illustrates a cross-sectional view of a balloon catheter with a stepped shoulder configuration according to the present disclosure.

FIG. 2B illustrates a cross-sectional view of a balloon catheter with a conical shoulder shape according to the present disclosure.

FIG. 2C illustrates a cross-sectional view of another balloon catheter with a stepped shoulder shape according to the present disclosure.

3A-C illustrate an example of a balloon catheter according to the present disclosure inflated to pressure.

Those skilled in the art will readily appreciate that the various embodiments of the present disclosure can be implemented by numerous methods and apparatuses configured to perform the intended functions. In other words, other methods and apparatus may be incorporated into this application to perform the intended functions. The accompanying drawings referred to in this application are not all drawn to scale and may be exaggerated to illustrate various embodiments of the invention, and in this regard, the drawings are not to be considered limiting. It shouldn't be. Finally, although the present disclosure is described in conjunction with various principles and beliefs, the present disclosure is not to be bound by theory.

In general, the present disclosure relates to devices, systems, and methods that reduce stress directly on a balloon seal.

With respect to FIG. 1, the present disclosure includes a balloon 100. Generally, balloon 100 includes a collapsed configuration and an expanded configuration. In the expanded configuration, balloon 100 further includes shoulder portions 110 at each end of balloon 100. The shoulder portion 110 is the area where the diameter of the balloon 100 circumferentially transitions between the larger diameter of the body or working length 120 of the balloon 100 and the smaller diameter of the seal portion 130 of the balloon 100. . As shown in FIG. 1, these shoulder regions may assume a substantially vertical and/or right-angled shape when inflated, rather than a tapered shape.

As illustrated, sealing portion 130 generally serves to secure balloon 100 around catheter 140 and provide a fluid-tight interface between balloon 100 and catheter 140. Catheter 140 typically includes an inflation lumen and an outlet (not shown) for inflating the balloon with an inflation medium. In one embodiment, the sealing portion 130 includes reinforcing features, such as multiple wraps of polymeric and/or adhesive-absorbed or deposited polymeric membranes on at least one side or at least partially of the film. For example, multiple wraps of ePTFE film at least partially imbibed with cyanoacrylate can be used to form the seal reinforcement.

Balloon 100 further includes a balloon cover that covers a substantial portion of balloon 100. As used herein, references made to a "balloon" refer to a "balloon cover" as the shape and structural forms described below apply to a balloon cover in the same or similar manner as to a balloon. shall also be construed to include.

Balloon 100 includes a compliant to sub-compliant material or a material used to construct limited expansibility balloons, such as a wrapped polymeric material. For example, balloon 100 includes one or more fluoropolymers, such as expanded polytetrafluoroethylene (“ePTFE”), expanded modified PTFE, expanded copolymers of PTFE, expanded polyethylene, and the like. In various embodiments, the balloon 100 may include helically, circumferentially, and axially oriented balloon walls, such as by wrapping an ePTFE film to form the balloon 100. As used herein, the term "axial" is interchangeable with the term "longitudinal". As used herein, "circumferential" means substantially perpendicular to a longitudinal axis. As used herein, "helical" means an angle that is neither parallel nor substantially perpendicular to the longitudinal axis. In various embodiments, the film is helically wrapped into a tubular shape to form a helically oriented balloon material. Orientation may refer to the direction of a particular property, such as strength or microstructural features, such as fine fibers.

Other materials with similar properties are also within the scope of this disclosure. For example, balloon 100 may be made of polymethyl methacrylate (PMMA or acrylic), polystyrene (PS), acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), modified polyethylene terephthalate glycol (PETG), cellulose acetate butyrate (CAB), etc. ) Amorphous general-purpose thermoplastic materials including polyethylene (PE), high-density polyethylene (HDPE), low-density polyethylene (LDPE or LLDPE), polypropylene (PP), and semi-crystalline general-purpose plastics including polymethylpentene (PMP) ; Amorphous engineering thermoplastics including polycarbonate (PC), polyphenylene oxide (PPO), modified polyphenylene oxide (Mod PPO), polyphenylene ether (PPE), modified polyphenylene ether (Mod PPE), thermoplastic polyurethane (TPU) Materials: including polyamide (PA or nylon), polyoxymethylene (POM or acetal), polyethylene terephthalate (PET, thermoplastic polyester), polybutylene terephthalate (PBT, thermoplastic polyester), ultra-high molecular weight polyethylene (UHMW-PE) Semi-crystalline engineering thermoplastic materials; high-performance thermoplastic materials including polyimide (PI, imidized plastic), polyamide-imide (PAI, imidized plastic), polybenzene-imidazole (PBI, imidized plastic); polysulfone (PSU), Amorphous high-performance thermoplastics including polyetherimide (PEI), polyethersulfone (PES), and polyarylsulfone (PAS); semi-crystalline high-performance materials including polyphenylene sulfide (PPS) and polyetheretherketone (PEEK) Performance thermoplastic materials; and fluorinated ethylene propylene (FEP), ethylene chlorotrifluoroethylene (ECTFE), ethylene, ethylene tetrafluoroethylene (ETFE), polychlorotrifluoroethylene (PCTFE), polytetrafluoroethylene (PTFE), It can be made from a variety of commonly known materials such as polyvinylidene fluoride (PVDF), semi-crystalline high performance thermoplastic materials including perfluoroalkoxy (PFA), and fluoropolymers. Other commonly known medical grade materials include elastomeric organosilicon polymers, polyether block amides or thermoplastic copolyethers (PEBAX). Additionally, expandable balloons may be made from urethanes, silicones, fluoroelastomers, elastomers, and polyether block amides.

According to the present disclosure and with respect to FIGS. 2A-2C, the shoulder portion 110 of the balloon 100 may include a load-sharing shape when inflated. Additionally, shoulder portion 110 of balloon 100 may include one or more load distribution members that facilitate a load distribution configuration when inflated.

The load distribution shape is generally any convex shape of the shoulder portion 110 of the balloon 100 that reduces stress directly on the balloon seal. Although not intended to be bound by theoretical values, circumferential and end stresses are directly proportional to the balloon diameter adjacent to the seal, so it is important to note that the circumferential and end stresses are directly proportional to the balloon diameter adjacent to the seal, so it may be necessary to It is thought that the amount decreases as the amount decreases. In this regard, the balloon 100 may include a longitudinally extending axis, and the outer edge 121 of the body portion 120 and the inner edge 131 of the seal portion 130 may be longitudinally offset or gapped. More specifically, according to non-limiting examples, the load distribution shape may include a stepped shape or a conical shape.

For example, and as illustrated in FIGS. 2A and 2C, the stepped shape has a diameter intermediate between the larger diameter of the body portion 120 of the balloon 100 and the smaller diameter of the seal portion 130 of the balloon 100. It may include one or more circumferential step portions 112 having a diameter. As illustrated, step portion 112 may include a circumferential ridge having a diameter smaller than the diameter of body portion 120. The ridges may be oriented substantially parallel to the longitudinal axis. The stepped balloon shoulder 110 may include at least two portions adjacent to the ridge that form an approximately 90 degree angle, although other angles greater or less than 90 degrees are within the scope of this disclosure. be.

As shown in FIG. 2B, the conical or tapered shape includes a circumferential taper 114 between the larger diameter of the body portion 120 of the balloon 100 and the smaller diameter of the seal portion 130 of the balloon 100. As illustrated, the taper 114 is at an angle of approximately 35-65 degrees, although angles greater or less than the ranges described are within the scope of this disclosure.

Other shapes, such as shapes that include a curved transition between the larger diameter of the body portion 120 of the balloon 100 and the smaller diameter of the seal portion 130 of the balloon 100, are also within the scope of this disclosure.

In various embodiments, a load distribution feature is provided on the shoulders of the balloon by one or more load distribution members. At least a portion of the load distribution member is less expandable than the body portion. The less inflatable load distribution member may be made of a material of greater hardness or stiffness than the material of the body portion, a material and/or construction less expansible than the body portion material or construct, or an intermediate diameter, i.e., more than the body portion of the balloon. It may include any material or construction that inhibits the shoulder portion from inflating beyond a diameter between the larger diameter and the smaller diameter of the balloon seal. In various embodiments, the load distribution member is present outside the body portion or working length of the balloon, e.g., the portion intended to contact the luminal surface of the endoprosthesis and/or the surrounding tissue, and is present in the shoulder portion. or extend only along the direction towards the seal of the balloon.

In some embodiments, the load distribution member facilitates a load distribution configuration but does not extend along a substantial portion of the shoulder 110; for example, the load distribution member extends along the midsection of the shoulder. Separate and provide. As a non-limiting example, as shown in FIG. 2A, the load distribution member may include a band 113 that facilitates the application of a circumferential step 112 and provides a stepped shoulder shape. In other embodiments, the load distribution member extends along a substantial portion of the shoulder 110. For example, as shown in FIG. 2B, the load distribution member may include a frustocone 115 extending along a substantial portion of the shoulder 110 such that the shoulder is conical or tapered in shape. Other shapes are also within the scope of this disclosure.

In other embodiments, the shoulder portion 110 may include multiple load distribution members, such as two or more bands 113, as shown in FIG. 2C.

In some embodiments, the load distribution member is a region of the balloon (eg, a band or frustoconical region) in which the balloon material is deformed. An example of such a modification is to densify the balloon material, such as ePTFE, along the target area of the shoulder. Such densification may be layered to create a tapered load distribution geometry. In various embodiments, densification is achieved by applying pressure and/or localized heat to targeted areas of the balloon material (eg, by sintering, laser treatment, patterned laser treatment, etc.).

Another such variation involves coating or absorbing materials that generally have low or no expansion (e.g., fluorinated ethylene propylene (FEP), PATT, thermoplastics, nylon, etc.) on the target area of the balloon shoulder. Including causing. For example, in illustrative embodiments involving ePTFE balloon materials, imbibing involves at least partially filling the pores of the porous ePTFE in the target area with a generally less expansive polymeric material.

In various embodiments, the shoulder portion may essentially include or consist of a second material that has a higher hardness than the material of the body portion of the balloon. In other words, the material of the body portion is not continuous along the shoulder portion from the body portion to the seal, and may sandwich the second material at least a portion of the shoulder portion.

In various embodiments, the load distribution member may be a structural reinforcement member (e.g., having the shape of a band or frustocone) added to the balloon region. Such structural reinforcement members may be located between balloon layers, between the balloon and the balloon cover, on the surface of the balloon, and/or behind the balloon wall. Such structural reinforcement members may be adhered to the balloon/balloon cover (such as by heat treatment and/or the use of adhesives) or otherwise secured in place. According to aspects of such embodiments, the structural reinforcement member may be a wrapped member, a molded member, a woven or knitted member, a die cut or laser cut member, or other suitably shaped reinforcement. May contain constructs.

For example, the structural reinforcement member may include a densified or imbibed material wrapped around a suitably shaped mandrel as described above.

For example, the structural reinforcing member may include a polymeric material having a higher hardness than the body portion formed (eg, blown or extruded) into the appropriate shape.

For example, the structural reinforcement member may include a pattern cut reinforcement member or similar structure. The pattern cut reinforcement member may include Nitinol or other similar shape memory material. For example, the nitinol reinforcing member may include a collapsible annular member, such as a stent ring, to facilitate stepped configuration. Alternatively, the Nitinol reinforcing member may include, for example, an annular base, which assumes a frusto-conical shape in the expanded state, which may be co-located with the seal, and which, when the balloon is inflated, has a frusto-conical shape. It may be formed with a plurality of nitinol braces extending from the band to form a conical load distribution shape.

Thus, in accordance with the present disclosure, the load-sharing geometry reduces stress directly on the balloon seal, thereby reducing the occurrence of malfunctions associated with balloon catheters.

Example of fabricating an ePTFE-wrapped balloon cover with a stepped load-distributing shape:

A stepped balloon is manufactured as follows. An ePTFE balloon cover (e.g., a cover containing wrapped ePTFE film) is placed on a mandrel with a first diameter (e.g., 8 mm) diameter up to a neck portion with a neck diameter of approximately 0.070 inch (1.778 mm). narrow or make smaller. The cover can then be expanded to about 4 millimeters and placed on a similarly sized mandrel. Anisotropic ePTFE film strips (width approx. 5mm) may be wrapped around the cover in the cover section that becomes part of the shoulder section. The film can be wrapped at least twice so that the tenacity direction of the film strip is oriented around the circumference of the balloon. The ePTFE film strip is a strong ePTFE with a density of 2 to 6 μm manufactured generally in accordance with the teachings of Kennedy U.S. Pat. No. 7,521,010, which is hereby incorporated by reference in its entirety. Good too. The thickness of the copolymer coating can range from 1 to 3 μm. The cover portion wrapped with 5 mm strips of ePTFE film is heat treated after wrapping to bond the layers together and between the layers and the cover. A cover can then be placed over the balloon and secured to the catheter at each end.

The covered balloon is inserted into a tube made of a material that is configured to shrink or contract at a specific temperature (e.g., FEP shrink tubing) and after positioning the covered balloon is heated at approximately 260 degrees Celsius. Can be heated. Covered balloons may be reduced in diameter or size from a 4 mm median diameter to about 0.100 inches (2.5 mm) using a radial crusher.

This allows the balloon to be manufactured in a step-like load-distributing shape, as described above. Figures 3A-3C show such a covered balloon 300 inflated to a pressure of 14 to 24 atmospheres. As can be seen, under low pressure, the difference between the diameter of the balloon of main body portion 120 and the diameter of circumferential stepped portion 312 is smaller than under high pressure, but the diameter of the main body of balloon 300 increases under high pressure. However, the circumferential step 312 cannot expand beyond the intermediate diameter.

It will be apparent to those skilled in the art that various modifications and changes can be made without departing from the spirit or scope of the disclosure. Therefore, it is intended that the embodiments described herein cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

In the foregoing description, numerous features and advantages have been set forth, including various alternatives, as well as structural and functional details of apparatus and/or methods. The disclosure is merely exemplary and is not intended to be exhaustive. Those skilled in the art will appreciate that the invention is understood to the fullest extent indicated by the broad general meaning of the terms expressed in the claims, particularly with respect to structure, materials, elements, components, shape, size and arrangement of parts. It will be obvious that various modifications may be made, including combinations within the principles of . These various modifications are encompassed by the present invention, provided they do not depart from the spirit and scope of the claims.

Claims (1)

a body portion inflatable to a first diameter and including a wrapped polymeric material;
two seal portions each having a second diameter smaller than the first diameter; and two shoulder portions each defining a transition between the first diameter and the second diameter.
A balloon comprising:
the at least one shoulder portion includes a load distribution member adapted to inhibit expansion beyond a diameter intermediate between the first diameter and the second diameter along a portion of the shoulder portion;
the at least one shoulder portion includes at least two vertical surfaces perpendicular to the longitudinal axis of the balloon, the at least two vertical surfaces including first and second vertical surfaces; a vertical face of the balloon extending from the second diameter to the intermediate diameter, and a second vertical face extending from the intermediate diameter to the first diameter.

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